Abstract: 18Ni(300) Steel had exceptional strength and toughness, which were used in the field of aviation and aerospace. In this study, using a high-speed tribo-tester, tribological behaviors of 18Ni(300) steel were investigated under high speed dry sliding conditions. Morphologies of the worn surfaces and the debris were analyzed by scanning electron microscope and the oxides of worn surfaces caused by friction heat were detected by X-ray diffraction. The results show that: friction coefficient of frictional pair declined with increasing load and speed; With increasing speed and load, oxides on worn pin surface varied from FeO to Fe₃O₄ and the wear mechanism transited from adhesive wear into severe oxidation wear.